Conventionally, there is known an injector holding structure which includes a metal port into which a tip of an injector can be inserted, a tapered ring having a predetermined tapered surface and fitted over the injector, and a nut fitted over the injector and having a tapered opening engaging with the predetermined tapered surface of the tapered ring, the nut locked to the metal port in a state in which the nut covers the tapered surface of the tapered ring. The injector holding structure is capable of securely holding the injector and improving the sealing performance.
However, the injector holding structure described above has a configuration in which the metal port is horizontally provided and the injector is horizontally inserted.
The injector holding structure varies depending on the process contents of a substrate processing process performed using the injector and the structure of a substrate processing apparatus. For example, when it is desired to introduce the injector to suspend from the upper surface of a processing chamber, the configuration described above is not necessarily a preferable configuration. In other words, when the injector is introduced to suspend from the upper surface of the processing chamber, it is important to adopt a support structure that prevents the injector from falling down.